Sakai, 1983
The carapace is a little broader than long. The front is obtusely bilobate, the median fissure is very shallow. The dorsal surface of carapace is uneven; immediately behind the frontal lobes, there is a pair of ridges and their outer edge is turn anteriorly and connected with the anterior edge of the orbital eave. Immediately behind these ridges, a pair of obscure nodule are present. In the gastric area, 3M is obscure, and behind, which a pair of small, rounded lobules are seen. The intestinal area is a little larger, represented by a small nodule. The hepatic and inner branchial areas are represented by small nodules, the former with a single and the latter with two oblique ones.
The antero-lateral border is composed of four sharp teeth, of which, the first or outer orbital one is very large, the second one is very small, the third one very large and the fourth is very small. The difference of size in these teeth are just like those of Ilyograpsus paludicola (Rathbun). Along the postero-lateral and posterior margins, there are rows of short intermitting ridges, otherwise, the surface of carapace is smooth.
The chelipeds and ambulatory legs are fallen off, also the 1st male pleopod is not seen. (Sakai, 1983)
Type locality: Kuira River, Iriomote-jima, Japan.
Range: Japan - Iriomote-jima (Sakai, 1983).